1. Field of the Invention
This invention relates to constructs, compositions and methods comprising multimeric forms of nucleic acid. One form of multimeric nucleic acid constructs comprise a streptavidin molecule bound with one or more single-stranded biotinylated nucleic acid molecules and an attached functional group. Constructs are used for the treatment or diagnosis of disorders both in vivo or in vitro, for the detection of target substances in samples and for construction purposes in nanotechnology and the creation of nucleic acid based polymeric aggregates.
2. Description of the Background
In recent years considerable interest has been generated in the use of anti-sense oligonucleotides and single-stranded DNA for in vivo therapeutic applications (G. Carter and N. R. Lemoine, Br. J. Cancer 67:869-76, 1993). Exciting examples include selective inhibition of viral DNA replication (C. K. Mirabelli et al., Anti-Cancer Drug Design 6:647-61, 1991) and gene expression (C. A. Stein and Y.-C. Cheng, Sci. 261:1004-11, 1993). The application of oligonucleotides into clinical medicine was encouraged by present advances with gene therapy such as the successful inhibition of viral gene expression in vivo by anti-sense DNA (M. Kulka et al., Antiviral Res. 20:115-30, 1991). Additional, in vivo applications have included oligonucleotide-antibody conjugates for tumor diagnosis and therapy (W. H. A Kuijpers et al., Bioconjugate Chem. 4:94-102, 1993).
Others have investigated, in animal models, the pharmacokinetics, biodistribution and stability of an array of oligonucleotides ranging in size from 12 bases (T.-L Chem et al., Drug Met Disp. 18:815-18, 1990), to as large as 38 bases (J. G. Zendegui et al., Nuc. Acids Res. 20:307-14, 1992), and labeled with radioisotopes such as .sup.125 I (D. R. Elmaleh et al., J. Nucl. Med. 34:232P, 1993), .sup.32 P (A. S. Boutorine et al., Bioconjugate Chem. 1:350-56, 1990), .sup.3 H (T.-L Chem et al., Drug Met. Disp. 18:815-18, 1990), .sup.35 S (S. Agrawal et al., Proc. Natl. Acad. Sci USA 88:7595-99, 1991), and .sup.111 In (M. K. Dewanjee et al., J. Nuc. Med. 34:174P, 1993). In these and other in vivo applications the nucleotide backbone was modified to stabilize the molecule against nuclease digestion, typically with methylphosphonates (D. M. Tidd and H. M. Warenius, Br. J. Cancer 60:343-50, 1989) or phosphorothioates (G. Goodarzi et al., Biopharm. Drug Disp. 13:221-227, 1992). Terminal modification alone was shown to provide sufficient stability in vivo (R. J. Boado and W. M. Partridge, Bioconjugate Chem. 3:519-23, 1992).
Amplification techniques for nucleic acids are under active investigation for in vitro applications. These include PCR (K. B. Mullis et al., Cold Spring Harbor Symp. Quant. Biol. 51:263-73, 1986), the "Christmas tree" approach (P. D. Fahrlnder and A. Klausner, Bio/Technology 6:1165-68, 1988), and branching nucleic acid dendrimers (R. H. E. Hudson and M. J. Damha, J. Am. Chem. Soc. 89:585-91, 1993). Each of these methods rapidly amplifies nucleic acid molecules in vitro to a very great extent. However, using nucleic acids for amplification in vivo has not previously been considered.